leetcode_num98_Validate Binary Search Tree

判断是否为二叉搜索树

定义上下确界

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    bool isValidBST(TreeNode *root) {
        return isValidBSTRe(root,LONG_MIN,LONG_MAX);//LONG_MIN,LONG_MAX set the bound
    }
    bool isValidBSTRe(TreeNode *root,long min,long max){//parameter type long
        if(!root)
            return true;
        else if(root->val<=min||root->val>=max)
            return false;
        else
            return isValidBSTRe(root->left,min,root->val)&&isValidBSTRe(root->right,root->val,max);
    }
};

leetcode_num98_Validate Binary Search Tree

原文：http://blog.csdn.net/eliza1130/article/details/44816115